mcs/class/corlib/System/__ComObject.cs

   1 //
   2 // System.__ComObject
   3 //
   4 // Authors:
   5 //   Sebastien Pouliot <sebastien@ximian.com>
   6 //   Kornél Pál <http://www.kornelpal.hu/>
   7 //   Jonathan Chambers <joncham@gmail.com>
   8 //
   9 // Copyright (C) 2004 Novell (http://www.novell.com)
  10 // Copyright (C) 2005 Kornél Pál
  11 // Copyright (C) 2006 Jonathan Chambers
  12 //
  13
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using Mono.Interop;
  36 using System.Collections;
  37 using System.Runtime.InteropServices;
  38 using System.Runtime.CompilerServices;
  39
  40 namespace System
  41 {
  42         // This is a private class that is used as a generic wrapper class
  43         // for COM objects that have no specific wrapper class.
  44         //
  45         // It has no public methods, it's functionality is exposed trough
  46         // System.Runtime.InteropServices.Marshal class and can be casted to
  47         // any interface that is implemented by the wrapped COM object.
  48         //
  49         // This class is referenced in .NET Framework SDK Documentation so
  50         // many times that obj.GetType().FullName == "System.__ComObject" and
  51         // Type.GetType("System.__ComObject") may be used.
  52
  53         internal class __ComObject : MarshalByRefObject
  54         {
  55                 #region Sync with object-internals.h
  56                 IntPtr iunknown;
  57                 IntPtr hash_table;
  58                 #endregion
  59
  60                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  61                 internal static extern __ComObject CreateRCW (Type t);
  62
  63                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  64                 private extern void ReleaseInterfaces ();
  65
  66                 ~__ComObject ()
  67                 {
  68                         ReleaseInterfaces ();
  69                 }
  70
  71                 public __ComObject ()
  72                 {
  73                         Type t = GetType ();
  74                         int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
  75                         Marshal.ThrowExceptionForHR (hr);
  76                 }
  77
  78                 internal __ComObject (Type t)
  79                 {
  80                         int hr = CoCreateInstance (GetCLSID (t), IntPtr.Zero, 0x1 | 0x4 | 0x10, IID_IUnknown, out iunknown);
  81                         Marshal.ThrowExceptionForHR (hr);
  82                 }
  83
  84                 internal __ComObject (IntPtr pItf)
  85                 {
  86                         Guid iid = IID_IUnknown;
  87                         int hr = Marshal.QueryInterface (pItf, ref iid, out iunknown);
  88                         Marshal.ThrowExceptionForHR (hr);
  89                 }
  90
  91                 private static Guid GetCLSID (Type t)
  92                 {
  93                         if (t.IsImport)
  94                                 return t.GUID;
  95
  96                         // look at supertypes
  97                         Type super = t.BaseType;
  98                         while (super != typeof (object)) {
  99                                 if (super.IsImport)
 100                                         return super.GUID;
 101                                 super = super.BaseType;
 102                         }
 103                         throw new COMException ("Could not find base COM type for type " + t.ToString());
 104                 }
 105
 106                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 107                 internal extern IntPtr GetInterfaceInternal (Type t, bool throwException);
 108
 109                 internal IntPtr GetInterface (Type t, bool throwException) {
 110                         CheckIUnknown ();
 111                         return GetInterfaceInternal (t, throwException);
 112                 }
 113
 114                 internal IntPtr GetInterface(Type t)
 115                 {
 116                         return GetInterface (t, true);
 117                 }
 118
 119                 private void CheckIUnknown ()
 120                 {
 121                         if (iunknown == IntPtr.Zero)
 122                                 throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 123                 }
 124
 125                 internal IntPtr IUnknown
 126                 {
 127                         get
 128                         {
 129                                 if (iunknown == IntPtr.Zero)
 130                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 131                                 return iunknown;
 132                         }
 133                 }
 134
 135                 internal IntPtr IDispatch
 136                 {
 137                         get
 138                         {
 139                                 IntPtr pUnk = GetInterface (typeof (IDispatch));
 140                                 if (pUnk == IntPtr.Zero)
 141                                         throw new InvalidComObjectException ("COM object that has been separated from its underlying RCW cannot be used.");
 142                                 return pUnk;
 143                         }
 144                 }
 145
 146                 internal static Guid IID_IUnknown
 147                 {
 148                         get
 149                         {
 150                                 return new Guid("00000000-0000-0000-C000-000000000046");
 151                         }
 152                 }
 153
 154                 internal static Guid IID_IDispatch
 155                 {
 156                         get
 157                         {
 158                                 return new Guid ("00020400-0000-0000-C000-000000000046");
 159                         }
 160                 }
 161
 162                 public override bool Equals (object obj)
 163                 {
 164                         CheckIUnknown ();
 165                         if (obj == null)
 166                                 return false;
 167
 168                         __ComObject co = obj as __ComObject;
 169                         if ((object)co == null)
 170                                 return false;
 171                         return (iunknown == co.IUnknown);
 172                 }
 173
 174                 public override int GetHashCode ()
 175                 {
 176                         CheckIUnknown ();
 177                         // not what MS seems to do,
 178                         // but IUnknown is identity in COM
 179                         return iunknown.ToInt32 ();
 180                 }
 181
 182                 [DllImport ("ole32.dll", CallingConvention = CallingConvention.StdCall, ExactSpelling = true, PreserveSig = true)]
 183                 static extern int CoCreateInstance (
 184                    [In, MarshalAs (UnmanagedType.LPStruct)] Guid rclsid,
 185                    IntPtr pUnkOuter,
 186                    uint dwClsContext,
 187                   [In, MarshalAs (UnmanagedType.LPStruct)] Guid riid,
 188                         out IntPtr pUnk);
 189         }
 190 }